Fluid pressure molding apparatus



Nov. 26, 1946.` y H. G. MORNR 2,411,743

FLUID PRESSURE MOLDING APPARATUS Filed sept. 2o, 1944 2 sheets-sheet 2ffffff I lT/URNEY Patented Nov. 26, 1946 UNITED STATI-:s PATENT. OFFICEApplication September 20, 1944, Serial No. 554,921 2 Claims. (Cl.144-281) The invention relates to apparatus for molding articles andmore particularly to new and useful means for molding plastic-bondedplywood or other plastic-bonded sheet material by fluid pressure.

Objects and advantagesof the invention will be set forth in parthereinafter and in part will be obvious herefrorn, or may be learned bypractice with the invention, the same being realized and attained bymeans of the instrumentalities and combinations pointed out in theappended claims.

The invention consists in the novel parts, constructions, arrangements,combinations' and improvements herein shown and described.

The accompanying drawings, referred tc herein and constituting a parthereof, illustrate one em- I bodiment of the invention, and togetherwith the description, serve to explain the principles of the invention,

Of the drawings:

Fig. l is a transverse section of a mold equipped with devices embodyingthe invention;

Fig. 2 is a similar view of a modified form;

Fig. 3 is a similar view of another modiflcation;

Fig, 4 is a fragmentary plan view of the mold shown in Fig. l;

Figs. 5, 6 and 7 are enlarged cross-sectional de tails of a vform offastening device used with the invention; and

Fig. 8 is an enlarged fragmentary plan ,view showing the fastener inplace.

The invention is directed to providing new and improved means forclosing the flexible casings or bags utilized in the molding ofplastic-bonded plywood, veneer or other fabric or plicated material whensame is molded into various shapes and articles by means of fluidpressure applied throughA a flexible membrane which lies between thesource of fluid pressure and the article being molded. The invention isapplicable, for example, to the method of molding disclosed in thepatent to E. L. Vidal et al., No. 2,276,004, dated March 10, 1942, butit will be understood that the invention is not limited to theparticular process and apparatus disclosed in said patent, but may beapplied gencontact with the material to be molded, it being erally tomolding operations and apparatus of the type broadly referred to above.

In such molding operations it is common to lay or place the veneers orother plies of material, inter-larded with thermo-plastic orthermo-setting resin, against the surface of the male or female mold andthen encase the mold and material to be molded within a flexiblemembrane such as a rubber bag. The bag -is then preferably exhausted soas to bring the membrane thereof into intimate mold.

most desirable to avoid air pockets and lack of contact throughout thesurface. vThis operation has heretofore involved considerable difficultyin fitting the bag to the mold and material. The bag has necessarilyrequired a large mouth or opening to enable it to be drawn over the moldand material, especially where the articles to be molded constitutelarge objects such as the wing or fuselage of an airplane. The matter ofencasing or sheathing the mold and article in the bag has been adifficult and awkward operation and the necessarily loose fit obtainedby the use of a bag having an opening large enough to encase suchobjects has led to looseness in the ultimate flt and the use of anundesirably large amount of extra material. In order to put the bagabout the mold and article it has been necessary to drag, pull andstretch the bag along, under and over the same. Also it is difficult towrap the bag or parts thereof about the mold and articles to insurecomplete coverage,

Moreover, great difficulty has been encountered in effecting a completeclosure and seal ofthe bag about the mold and article in order toproceedl with the molding operation. The molding operation entailsapplication of fluid pressure and heat to the exterior of the bag whileVpermitting the interior thereof to exhaust to atmosphere or a lowerpressure zone, all as more fully disclosed in said Vidal et al. patent,for example. Where the bag is not tightly closed, heat and moisturepenetrate such closures and frequently impair or loosen the mold or thearticle being. molded or bonded. Similarly, where a close and accuratefit between the bag and the enclosed article is not obtained, the

heat and pressure sometimes cause the poorly fitted portion of the bagto stretch across depressed surfaces in the enclosed article and thusweaken or break the bag at such point, causing .destruction of the bagand of the articles therewithin.

Objects of the invention are to provide devices for improving the fit ofbags or membranes insuch molding operations; and to provide com-lpletely fluid-tight closuresr4 thereof which can be quickly andeiliciently closed and opened throughoutl the entire lengthor breadth ofthe These features of the invention permit rapid insertin and withdrawalof the articles being molded; avoid the necessity for overlapping andwrapping bags or layers thereof about such articles and molds; permitthe shaping of the bag to the mold and Aarticle so that a c lose andaccurate fit is obtained automatically upon clo- "animee of the bag ormembrane it is desired to close and,

because of its flexible nature, the closure will conform lexactly to theshape to be taken by the bag or membrane against the mold and articlewithin it. Because of the fact that such closure can be of indefinitelength, the opening of the bag can be made throughout its length orbreadth or both, thereby permitting same to be laid fully open for theeasy insertion of the material to i be molded within the mold (female)or readily brought around the exterior of a male mold, as the case maybe.

It will be understood that the foregoing general description and thefollowingdetailed description as well are exemplary and explanatory butare not restrictive of the invention.

Referring now to the present preferred embodiment illustrated by way ofexample in the accompanying drawings, there is shown diagramrial, whichsheet is permanently and hermetically bonded by plastic or other meansto the plane surfaces I. Thus it will be apparent that the closuremembers 3 and 4 may be drawn together by suitable slide fastening meansso that the entire blanket I| will be closed and sealed over and aboutthe molds |00 and |03 and the enveloping article or material |00 to bemolded.

The embodied means for effecting the slidefastening closure comprisesthe two major fiexible rubber bodies or strips 3 and d adapted to beoperably engaged in interlocking longitudinal relationship. Each of saidstrips il and d extends throughout the length of the opening to beclosed, is made of relatively thick but pliable and yieldable rubber,preferably of about theconsistency of automobile tire rubber or slightlysofter. Each of said strips is therefore inherently iiexible throughoutits length and thus is adapted to conform to the-shape of the containeror of the contents thereof. The strip 3 (Fig. 5) is formed as a solidrubber body having a flat base portion 5 which tapers to a relativelythin side edge portion or strip 0. The flat base 5 is adapted to bematically in Fig. l a form of mold |00 for shaping l or molding part ofthe surface of an airfoil or aircraft wing, for example. This mold maybe similar in principle to those shown in Vidal Patent No. 2,276,004,British Patent 443,696v t0 Groves, and the like, and it is understoodthat the detailed construction of said mold and the part to be moldedthereon constitute no part of the present invention and are here shownas suggestive and illustrative only of the principle of the presentinvention. Said mold cmprises the generally rectangular base or block|00 having the concave portion |02 forming the lower surface and tailand nose curves of the Wing. A male mold block |03 may be seated withinsaid outer mold |02 and upon said male mold there will be laid strips ofveneer |04 which are suitably coated or impregnated withthermo-responsive plastic material which acts under he'at and pressureto bond and integrate and mold together the various layers of veneer orother fabric macasing which, as shown, comprises the overlying rubberblanket H0, the edges of which lie upon the plane border surfaces ||I ofthe mold block |00. The peripheral edge of said blanket ||0 is providedwith` a beaded closure member 3 formed of rubber or other exiblematerial, which member is preferably' shaped and constructed as shownand described in detail in my Patent No. 2,355,816. Said memberpreferably extends along the entire periphery of the blanket ||0 andwhen said blanket is laid in the mold-covering position shown in Fig. 1,said closure member 3 is adapted to be engaged with the mating closuremember 4 which is fastened to the plane border surface of the/block |00.As shown, said mating closure member d is fastened to said bordersurface I|| of the block, being formed as an integral bordering part ofa sheet llt ofrubber or other mateseated on and vulcanized to the outersurface of the membrane or blanket ||0, while preferably an overlappingsealing strip l is contiguously sealed to the outer surface of membraneIIO and overlies the thinner portion 6 and is vulcanized thereto so asto form a strong and fluid-proof and flexible connection between thestrip body 3 and the membrane I |0. Similarly body strip member 4 ispermanently sealed and fastened to the membrane ||4 by `similar parts aswill -be clear from the drawings.

The strip members 3 and 4 are adapted to be intermeshed and separablyinterlocked throughout their length andtheir adjacent surfaces aresuitably formed for this purpose. As will appear from Figs. 5 and 6,.the strip member 3 is the primary female member of the closure pair, itsin- "ner or meshing surface being formed with a groove or socket-likerecessv I0 which extends throughout the length of the member. The socketor groove I0 is formed by an upper node or ridge Il, the terminal edgeof which is arcuate. A lower node or ridge underlies the socket |0 andcurves outwardly and upwardly from the interior thereof to provide anupper terminal edge I3. Said edge I3 and the opposite and adjacentterminal edge I4 of the node are spaced closer to each other than themaximum cross-sectional diameter of the socket I0 so that said sockethas a mouth or entrance smaller in cross-section than its interiorsection. The upper surface of the node I I is reversely curved at I5 toform 'a rounded top for the member 3 which continues in a substantiallyuniform arc around the surface thereofrto form a re-entrant groove I6along the back edge of the member 3 and at about the same level as thelower portion of the rsocket I0. 'I'he tapered upper surface of the basemember 5 extends into the groove i6 as shown. The lower surface of thelower node I2 curves downwardly and rearwardly to terminate at a slightshoulder I8 formed in the fiat base of the portion 5.

The strip I constitutes the primary male member of the closure coupleand its engaging or front face is provided throughout its length withprotruding node 20 which is substantially circular in cross-sectionthroughout about three-fourths of its cross-sectional circumference andis shaped and positioned so as to flt very tightly into thesocket-portion I0 of the member 3. The rear or neck portion 2|` of thenode 20 is narrower than portion of the member llip portion 23 themaior-diameter of the .node and thus is 1 stantial extent. It will benoted that the terminal edge of the lip member 23 is in substantiallythe same vertical plane as the terminal edge of the node member 20. I'heupper surface' of the is rearwardly and downwardly curved in an arcshape to that of the surface I5 of member 3 and being re-entrantlygrooved at 25 along the rear edge of the member 4, which groove mergeswith the rising surface of the tapered base 5 so as to form a grooveidentical in shape with and atl the same level as the groove i3 of themember 3 but .facing in the opposite direction, as will be clear fromthe drawings.

The lower portion of the node 20 merges with a reversely curved groovedportionl 23, the crosssectional outline of which corresponds intimately`with the node I2 of the member 3.- Below the groove 23 the member 4curves` inwardly and downwardly to form the relatively thin and flexiblelip portion 21, the base of which is cc-extensive with the fiat base ofportion 5. The inner edge of lip 21 extends so as to underlie the curvedsurface I1 of the portion I2 of member 2 and f abut against the'shoulderI3 of member 3 when the strips are in their interlocked engagement,v

as wm be clear from Figs. 6 and '1.

. 6 construction therefore greatly facilitates the /slldi118 engagementand disengagement of the strip members, while at the same time thesealing actions of the flexible lip members 23 and 21 provides a uniquesealing function in combination with the main interlock as abovedescribed.

The invention provides means for joining and closing togetherthe strips3 and 4 of the closure 2 4 roughly corresponding-in of slide action andone important feature of the invention is the construction of slidemeans which will reduce to a minimum the friction and resistance to suchclosures under all conditions of use of the device, while at thesametime providing the maximum of tightness and compression of the engagingparts of the closure strips -so as `to provide and maintain anexceedingly tight, and therefore effective, sealing closure.

For this purpose a rolling and compressing action is preferablyemployed. As embodied the slide comprises a frame having a flat,generally rectangular metal base piece which overlies and is spaced ashort distance from the top of the outermost portion ofthe lip 23 of thestrip mem- When the strips 3 and 4 are inter-engaged as described andshown, the central node portion 20 is tightly interlocked within thereceiving socket 'I0 of the member 3. That is, it is necessary to forcethe member 20 into the vsocket I0 between the constricting jaws I3 andI4 of the latter, the resiliency ofthe rubber permitting this action. Atthev same time the lower node I2 and the upper node il of the member 3are recessed in the sockets 26 and 22 respectively of the member 4 sothat a firm union and interlocking closure isaiforded by these parts. Inaddition, however, the overlapping relatively thin and pliable lip 23embraces and overlies the entire joinder of the strips. This lip membertherefore forms an effec- 'tive seal to the entire closure or joint and.be-

cause of its thin-ness and relative pliability, it is adapted to beforced tightly against the upper surface I5 of member 3 when the closureis subjeoted to external fluid force during the molding operation. Thatis, the fluid pressure exerted against fthe surfaces of the container orblanket tends to compress and thereby tighten the closure of the entirejoint and especially to' force the overlying lip 23 tightly over andagainst the surface I5 and thereby effectively seal the entire joint. Ina similar manner the underlying, relatively thin tapered lip 21 performsalike function for the lower portion of the closure as will be obviousfrom the foregoing taken in connection with the drawings.

It will be notedthat the engagement of node II in the socket 22 and nodei2 in socket 25 are relatively easily separated by transverse movementlas there is little or no interlocking action at these surfaces, the onlytrue interlock being between the socket I0 and the node 20. This ber 4,said plate 30 thus lying parallel to the base 5 and the face of themembranes I and 2. Each of the four corners of the plate 33 is apertureqto receive a vertically-disposed pin 3I having an enlarged head 32 thebase of which lies flush against the top of the plate. Said pin extendsdownwardly from the plate a sufficient distanceto serve as an axle or-journal for a roller 33 which is rotatable thereon. Said roller has .anupper cylindrical portion, the top of which underlies the bottom surfaceof the plate 33 and therebelow the surface ofthe roller is curved asshown in Fig.v 6, said curvature being such. that the roller is circularin cross-section throughout but of diminishing radius nearly to itsbottom portion where it again flares to terminate in a circular hub 35.Said hub has a roundedl edge ofl a thickness such that it fitsintimately into the groove 25 of the strip member 4 (or groove I'S ofstrip member 3 as the case may be) while the rear curved portions 24 andI5 of the strip members 4 and 3 respectively fit generally into thecurved surfaces 34 of the rollers. It will be understood that each ofthe rollers 33 at the four corners of the plate 30 is identical inconstruction and that each of them is rotatable on its respective axlepin 3i as shown. VThe lower ends of said axle pins 3l are enlarged at 35to be seated in conforming recesses at the base 35 of the rollers andthereby act to rotatably support said rollers as shown.

As will be clear from the drawings, movement of the slide 3 0 lengthwiseof the strips 3 and 4 will cause the rollers to rotate due to thefrictional engagement thereof with the outer or rear in the grooves I6and 25 and thereby exert powerful clamping and compressing action uponthe strips so as tocause the interlocking nodes 20 and I2 and theirrespective socket portions to be forced4 quickly and rmiy together. Dueto `the seating of the hubs 35 in said grooves, the

slide is at all times intimately engaged with the strips 3 and 4wherever it may be located along them andmerely by pulling it lengthwisealong said strips it forces the unengaged strips together as stated andshown. It will be recognized that by the'utilization of rollingfriction, a`

any and all conditions.

relatively great compressive force can be exerted upon the strips whileat the same time assuring easy operation of the slide along the stripsunder v,of the slide in one direction will effect closure andinter-engagement of the strips 3 and 4.

-However, a reverse movement of the slide will not automaticallyseparate the strips, but will Moreover the provision chains 60 and 6|are provided for this purpose. Said chains preferably comprise linksseparated by small beads 62., Each arm of the spacer membei' 50 isapertured by a slot 53 -the outer portion of which is narrow and whichis enlarged terminally to permit passage of the link portion 60 of thechain but is too small to admit passage of the bead members 62 thereof.Thus any pull on the merely make their separation possible by hand.

Thus the closure of a bag. for instance, will re-` main water-tightuntil it is actually opened.

Means for facilitating sliding of the slide on the vstrips is providedand same is constructed so as to further reduce any possibility of theslide tov tilt or assume an undesired angular position on the strips ineither direction of movement therealong. As embodied a slide pullcomprising a pair of looped cords 40 and 4| is provided, the ends ofsaid cords being passed through a button or apertured handle member 42and knotted at 43. The opposite ends of said cords are passed throughlongitudinal slides 45 and 46 respectively formed in the slide plate 30.Thus when it is desired to pull -the slide upwardly to close the stripstogether, the cord loops will slide to the upper ends of the slots 45and 46 and the pull will be exerted there substantially parallel to theplane of the slide 30 and the direction of desired movement.

downwardly in the opposite direction, the looped cords will slip to thebottom of the slots and 46 and thus the pull will be exerted at thelower end of the slide and therefore more closely parallel to thedesired plane of movement. In other words, no tilting action is impartedto the. slide or carriage in either direction of movement 4 thereof aswould be the case if the point of ap- .plication of the pulling forcewere xed at the center or at either end of the slide. Hence binding orwedging of the slide on the strips is materially reduced by this featureof the invention.

The invention provides additional means for maintaining compact closureand security there- Aof throughout the length of the strips 3 and 4 overwhich the slide 30 has been moved in the closing direction., For thispurpose a plurality of slide following members 50 are provided, saidmembers being adapted to be drawn after the slide 30 and to maintain thecompactness of closure which has been effected thereby. Said followingmembers 50 are preferably substantially U- shaped pieces of flat metal,the interior curvature of which conforms substantially to the exterioroutline of the curved portions I5 and 24 of the strips 3 and 4 when thelatter are inter-engaged. Inwardly disposed tongues 5| and 52 areprovided near the 'ends of the arms of the member 50 and extending intoand travelling along the grooves I6 and 25 respectively, there acting tomaintain the pressure and compacting force originally exerted by thehubs 35 of the rollers 33 of the slide.

Means are provided for drawing the followers 50 after the slide and formaintaining same in suitable spaced positions along the closed parts ofthe strips 3 and 4. As embodied each of the followers A50 is attached toexible cords or chains along either side of the strips ,and as shownchains in either ldirection will. cause the follower members 50 to slidealong the strips. The chains at one end are fixed to the slide plate 30,the lower ends 65 thereof being downwardly flanged at 66 to providemeans for attachment of ythe endsv of said chains. The flanged portions66 areapertured at 61 in form similar to the apertures 53, there toreceive the end link and bead of the chain as shown. Thus when the slideis pulled upwardly, it pulls the chains 60 and 6| along with it and inso doing causes the followers 50 to be pulled along the strips to takeup their spaced positions along the taut chains. Preferably, thefollowers are provided in sets of pairs spaced by a single bead 62 thusproviding a distribution of gripping action at each pair of saidfollowers.

The bottom ends of the strips 3 and 4 are pref- -erably maintainedlpermanently interlocked together and for this purpose an arcuate or U-shaped band 10 is tightly gripped about the elevated portions of thestrips as shown in Fig. 8. The terminal ends are tightly embedded intothe grooves |6 and 25 respectively of the two strips so that said band10 is tightly fixed and stationary near the lower ends of said strips.The bottom ends of the chains 60 and 6| are fixed to said band 10 byears I5 which extend toward the sides of said band and are provided withappropriate openings 16 to receive and hold the ends of said chains asshown.

Thus in the embodiment described above, it will be seen that completeand rapid closure of the molds and article to be molded may be effectedsimply by laying the properly shaped blanket ||0 thereover and sealingsame to the mold block |00 by means of the slide fastener operation4described above. .Consequently the blanket. ||0 may be accordinglyshaped to oo nform to the mold and article without any slack or wrinklesand without'requiring any close setting or manipulation during or afterthe application thereof. At the same time the closure effected by theabove-described means is fluid-tight even under the pressures andtemperatures yused for the molding operation so that no danger ofleakage or rupture is involved.

Referring to the modification of the invention shown in Fig. 2, the moldblock |00, the molds |02 and |03 and the article |04 to be molded aresubstantially the same as those shown in Fig. 1. However, with this formof the invention the closure members 3 and 4 are located along anintermediate line of the overlying blanket which comprises two separatepieces |20 and |2|. The edges of the piece |20 are sealed to the upperborder surface of the mold block as by an overlying metal or otherhermetic sealing member |25, while the similar edges of the piece |2|are similarly sealed by means |26. The closure members 3 and 4 may andpreferably do extend throughout the length of the mold and blanketmembers |20 and |2| so that same may be laid back to either side of themold for the insertion of the slide fastener as previously described. It

- will conform even along the edges of the closure to the surfaces to bemolded therewithin. Thus a completely tight and accurate iltting oLthemembranes is assured throughout the length of the bag or membrane means,while a completely fluid-tight closure is effected in a position mostenvenient for insertion and removalof the mold or articles to be molded.The work need not be dragged along in contact with the blanket ormembrane during the closing and tting operations nor will the blanket ormembrane be dragged or brought in contact with the fioor or othersurfaces while putting the assembly in the autoclave for heating andapplication of pressure. The minimum surface and quantity of materialfor the uid-tight membraneis providedby this and the first form of theinvention described while a minimum of handling thereof isl entailed inboth cases.

. Referring to the form of the invention shown in Fig. 3, same is thereshow-n as applied to a baglike membrane which is wrapped around orcompletely envelopes the mold and article to be mold-4 ed, as in Fig. 2of said Vidal patent. for example. In this form the male mold i3lllispositioned'with vthe materials I3! to be molded thereabout and thisassembly is surrounded by a bag or membrane comprising a continuousblanket |35 which, as shown, completely envelopes ,the mold and article.The closure of said bag or envelope is eectedby the closure members 3and 4 provided throughout the length of the opening or mouth of saidbag, said opening and closure members preferably extending throughoutthe length of said bag. Here again the minimum amount of blanket ormembrane material is required to completely envelope the mold andarticle and same may be drawn tightly into conformity therewith by theact of closing the bag as already described.

The invention in its broader aspects is not limited to the specincmechanisms 'shown and described but departures may be made therefromwithin the scope or the accompanying claims without departing from theprinciples oi' th invention and without sacrificing its chiefadvantages.

What I claim is:

1. In uid pressure molding apparatus in combinatlon,l a mold curved inat least two directions and adapted to have material to be molded inContact therewith,\ a ilexible `huid-impervious membrane positioned tocover said mold and material, the membrane being shaped and sized to'conform closely to said mold and material, means for subjecting the faceof the membrane remote from the mold and material to fluid pressure andmeans for venting the opposite face thereof to a lower pressure, and anopening in said membrane, the edges of said opening being formed asilexible mating strips of yieldable material, and a slide member forjoining said strips in a fluidtight closure, said closure beingsubstantially coextensive with one of the major axial dimensions of themold.

2. In iiuid pressure molding apparatus in combination, a curved moldadapted to have material to be molded in contact therewith, a flexiblefluid-impervious bag for enclosing said mold and material, said bagbeing shaped and sized to conform closely to the mold and materialtherewithin, means for subjecting the face o1 the bag remote from themold and material to fluid pressure, means for venting the opposite facethereof to a lower pressure, and an opening in said bag substantiallycoextensive with one of the majoraxialjdimensions of the mold, the edgesof said opening being formed as flexible mating strips.,of yieldablematerial joinable together in a fluidtight closure, said closure -beingcontinuous throughout the length of said opening and flexibly movablewith the walls of the bag in respect to the mold.

HANS G. MORNER.

